Rotary control valves with pressure-reducing means

Abstract

The rotary control valve comprises a casing having a pair of axially-opposed ports. A valve chamber is rotatably mounted in the casing. A stem adjustably rotates the valve chamber for controlling the flow through the ports. The valve chamber has a pair of axially-opposed, off-center orifices, each being contiguous to and movable into and out of partial and full registration with its associated port. An off-center tube is disposed inside chamber and extends between the orifices. A pressure-reducing medium in the valve chamber. The medium includes a plurality of stacked, axially-spaced discs, each having a pattern of axial holes for dividing the flow thereacross.

What I claim is: 
     
       1. A rotary control valve, comprising: a casing having a center axis and defining a pair of axially-opposed, inlet and outlet ports;   a valve chamber in said casing, said chamber having a pair of axially-opposed, off-center inlet and outlet orifices operatively and respectively associated with said inlet and outlet ports;   a valve stem extending through said valve chamber and having an axis of rotation coaxial with said center axis for adjustably rotating said chamber in said casing about said axis of rotation;   each orifice being contiguous to and movable into and out of partial and full registration with its cooperating port, and said orifices being shaped for controlling the flow through said ports;   means including said orifices for providing a predetermined pressure reduction for each adjusted angular position of said valve chamber; and   an off-center discharge tube disposed inside said cavity substantially parallel to said stem, and said tube extending between said orifices.   
     
     
       2. A rotary control valve, comprising: a casing having a longitudinal center axis and defining a generally cylindrical internal receptacle having a pair of inlet and outlet, axially-opposed flow ports;   a rotatable stem extending through said receptacle and having an axis of rotation coaxial with said center axis;   a valve control element disposed inside said receptacle and being mounted on said stem for rotation therewith, said element including a valve chamber having a cylindrical sleeve, an upstream circular plate, and a downstream circular plate, said upstream plate having an inlet orifice and said downstream plate having an outlet orifice, each orifice being suitably shaped to provide a desired flow therethrough in relation to the rotation of said stem; and   a tubular member disposed inside said valve chamber and extending between said orifices, said member having a bore whose opposite open ends become in full registration with said inlet and outlet flow ports when said valve chamber is in its fully-open position, and when said valve chamber is in its throttling positions, fluid flows in from said inlet port into said valve chamber through said inlet orifice and follows a path outside said tubular member, and fluid flows out from said valve chamber into said outlet port through said outlet orifice.   
     
     
       3. A rotary control valve, comprising: a casing defining an internal receptacle having a pair of inlet and outlet flow ports;   a rotatable stem extending through said receptacle;   a valve control element having a valve chamber disposed inside said receptacle and being mounted on said stem for rotation therewith, said valve element including a valve chamber having a cylindrical sleeve, an upstream circular plate, and a downstream circular plate, said upstream plate having an inlet orifice and said downstream plate having an outlet orifice, and each orifice being suitably shaped to provide a desired flow therethrough in relation to the rotation of said stem;   a tubular member disposed inside said valve chamber and extending between said orifices, said member having a bore whose opposite open ends become in full registration with said inlet and outlet flow ports when said valve control element is in its fully-open position; and   a driver operatively coupled to said valve for rotating said stem and said valve chamber.   
     
     
       4. The valve of claim 2, wherein each orifice is contiguous to and movable into and out of partial and full registration over its associated port and cooperating therewith to gradually throttle the fluid flow between said ports.   
     
     
       5. The valve of claim 4, wherein each orifice is transverse to the plane of its orifice plate and offset from said center axis, and each orifice defines a near-circular aperture followed by an elongated tapering arcuate channel of gradually restricted width.   
     
     
       6. The valve of claim 5, wherein said tubular member has a straight cylindrical bore of the same diameter as said flow ports, and the opposite open ends of said bore being in full registration with said flow ports when said control element is in its fully-open position, whereby said flow ports and said tubular member form a straight, full-bore flowway having a longitudinal axis which is radially offset from and parallel to said center axis.   
     
     
       7. The valve of claim 6, and a pressure-reducing medium in said valve chamber disposed around and surrounding the external wall of said tubular member, said medium being adapted to cause a tortuous flow therethrough to provide a stepped pressure reduction in the flow through said valve chamber.   
     
     
       8. The valve of claim 7, wherein said pressure-reducing medium includes a plurality of stacked, disc-shaped members spaced from each other to provide a flow path therebetween, each disc-shaped member defining a plurality of axial holes therethrough and a center circular opening, and said tubular member extending through and being secured to the circular openings in said disc-shaped members.   
     
     
       9. The valve of claim 7, wherein said pressure-reducing medium includes a block of material having a plurality of axial holes in the direction of flow and a straight-through, cylindrical center bore, and said tubular member extending through and being secured to said center bore.   
     
     
       10. The valve of claim 8, wherein fluid flowing from said inlet port through its associated channel flows into said valve chamber and follows a path outside said tubular member through the entire volume of said pressure-reducing medium, and flows out through the opposite channel into said outlet port.   
     
     
       11. The valve according to claim 1, wherein each orifice includes a near-circular aperture which is followed by a gradually tapering channel, said discharge tube extending between said apertures, and said valve chamber allowing full-bore fluid flow only through said discharge tube when said apertures in said orifices become opposite to and in full registration with their cooperating ports.   
     
     
       12. The valve according to claim 11, wherein said tapering channel is elongated, arcuate and being defined by walls converging toward their trailing ends.   
     
     
       13. The valve according to claim 1, wherein said means is a pressure-reducing medium disposed in said valve chamber, and the entire medium being operative for dividing the fluid flow through the valve chamber into a plurality of tortuous streams for any adjustable angular throttling position of the valve chamber.   
     
     
       14. The valve according to claim 12, and said means is a pressure-reducing medium disposed in said valve chamber, and the entire medium being operative for dividing the fluid flow through the valve chamber into a plurality of tortuous streams for any adjustable angular throttling position of the valve chamber.   
     
     
       15. The valve according to claim 14, wherein said pressure-reducing medium includes a plurality of stacked, axially-spaced, disc-shaped members, each member having axial holes therethrough of predetermined diameters depending on the desired pressure drop across said medium.   
     
     
       16. The valve according to claim 15, wherein each disc-shaped member includes an off-center bore, and said tube extending through all the bores in said disc-shaped members.   
     
     
       17. The valve according to claim 16, and a drive shaft coupled to for rotating said stem in response to the desired pressure drop across said valve chamber.   
     
     
       18. The valve according to claim 17, wherein said valve chamber has an angular throttling range between 180° and 280°.   
     
     
       19. The valve of claim 17, wherein fluid flowing from said inlet port through its associated channel flows into said valve chamber and follows a path outside said tubular member through the entire volume of said pressure-reducing medium, and flows out through the opposite channel into said outlet port.   
     
     
       20. The valve of claim 14, wherein said pressure-reducing medium has a plurality of balls of a suitable material.   
     
     
       21. The valve of claim 1 wherein said orifices are geometrically distinct. 
     
     
       22. The valve of claim 1, wherein one of said orifices is substantially full-bore throughout its length.   
     
     
       23. The valve of claim 3, and means for adjusting said driver in accordance with line pressure variations to maintain a desired output pressure from said valve.   
     
     
       24. The valve of claim 23, wherein said output pressure is constant.   
     
     
       25. The valve of claim 2 wherein said casing is a split casing to allow the removal of said valve control element therefrom after said casing is installed.